TEHRAN, Iran (CNN) -- Militants detonated a percussion bomb at a girls school in southeastern Iran and opened fire on an electricity plant before fleeing and hiding in a nearby house in Zahedan, according to a Iranian news agency's report.

No one was hurt in the blast, according to the Islamic Republic News Agency.

A percussion bomb is also known as a "sound bomb," and is used to cause distraction.

Police shot at the gunmen as they ran into a residential complex under construction Friday night, the city's governor Gen. Hassan-Ali Nouri told IRNA, adding that the blast was "just a blind operation."

On Saturday, IRNA reported that police had restored order in Zahedan, a town at the juncture of the borders of Iran, Afghanistan and Pakistan.

Gunfire was heard after security forces blocked off streets near the bombers' hideout. Police cut off the electricity to the housing complex, the semi-official FARS news agency said.

Abdolmalek Rigy, the leader of the Jondollah militant group, told MKO-TV that said his group was responsible for the bombing, FARS reported. However, MKO officials told CNN they aired no such claim.

MKO stands for the Mojahedin Khalq Organization, which the Iranian government considers a terrorist group stationed in Iraq.

The Jondallah group claimed responsibility for a car bomb in the same area Wednesday, Iranian officials said. Eleven people were killed and 30 more were wounded after a car bomb ripped through an Iranian military bus in Zahedan. (Full story)

The bus belonged to the Islamic Revolutionary Guards Corps, and a witness told IRNA that the car exploded as the bus arrived to pick up military personnel at a barracks. Five people, including a failed suicide bomber, were arrested after the Wednesday attack, IRNA reported.

Jondollah has a history of attacking Iranian border posts, according to Iranian news agencies.

Zahedan is on a busy route used by smugglers to traffic contraband, such as opium, through Iran.